It is a well known problem that safes are sometimes subjected to mechanical damage in connection with burglaries. If the burglary is successful, currency and other negotiable documents stored in the safe can be used by the burglars despite substantial damage to the safe.
Insurance companies normally assign each type of safe a highest value of the content stored therein, for which compensation can be given by the insurance company in the event of a burglary. Amounts in excess thereof stolen from such a safe are not reimbursed by the insurance company. Due to, among other things, inflation, older safes thus have a lower and lower "utility value" for the user and it would be desirable to be able to increase the amount which can be stored in the safe.
In order to discourage burglars from breaking into safes and at the same increase the monetary value which can be stored in old or new safes, the present invention is suggested.
It is of course previously known to place special boxes or cassettes in large safes or strong-boxes. These boxes are normally only provided with ordinary locks, but they can also be provided with combination locks. The boxes are often pre-mounted at the factory and are often provided with some sort of alarm device.
One example of the latter is described in Austrian patent specification No. 381976, where a safe with an inner module is provided with an electronic monitoring unit.
U.S. patent specification No. 952,761 describes providing a safe with an inner box, the door of which is mechanically coupled to a tube element containing chemicals designed to discolor currency and negotiable documents stored in a compartment in the box. The tube element is broken mechanically if the door to the box is opened in an improper manner.